Communication method and transmit end device with listening capability

ABSTRACT

This application discloses a communication method. The method includes: comparing, by a second transmit end device, a second bandwidth carrying at least one second service transmission and a first bandwidth, wherein the first bandwidth is used by a first transmit end device within a first specified time period on an unlicensed frequency band to complete first service transmission, the at least one second service transmission started in a remaining time period of the first specified time period after the first service transmission is completed; performing channel listening on the second bandwidth based on a result of the comparison; and performing, by the second transmit end device, the second service transmission on the second bandwidth if the second bandwidth is found to be in an idle state. In addition, a corresponding transmit end device is disclosed. This application discloses a channel listening mechanism applicable to a flexible-bandwidth scenario.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/656,282, filed on Oct. 17, 2019, which is a continuation ofInternational Application No. PCT/CN2018/083347, filed on Apr. 17, 2018.The International Application claims priority to Chinese PatentApplication No. 201710250043.9, filed on Apr. 17, 2017. All of theafore-mentioned patent applications are hereby incorporated by referencein their entireties.

TECHNICAL FIELD

The present disclosure relates to the field of communicationstechnologies, and in particular, to a communication method and atransmit end device.

BACKGROUND

Rapid development of wireless communications technologies leads to anincreasing shortage of spectrum resources, driving exploration onunlicensed frequency bands. A next-generation mobile communicationssystem, for example, a 5th generation mobile communications system,needs to support a huge growth of mobile data traffic. Therefore, use ofunlicensed spectrum resources is of great attraction to next-generationmobile communications (for example, new radio (NR)). Since there is noneed to purchase the right of using unlicensed frequency bands, transmitend devices can use these spectra as needed, provided that theseunlicensed frequency bands can be used fairly among the transmit enddevices. Channel listening means determining, by listening to signalpower on a channel, whether the channel is occupied, and is an effectiveway to ensure that unlicensed frequency bands are used fairly.

In a licensed assisted access (LAA) or an enhanced licensed-assistedaccess (eLAA) system, a system bandwidth is fixed in a transmissionprocess. Before performing transmission, a transmit end device needs tofirst perform channel listening on a corresponding system bandwidth, andcan perform transmission only when the transmit end device detects thata corresponding spectrum is idle.

However, all existing channel listening mechanisms are applicable tofixed bandwidths, and up till now, no clear and effective solution isyet available for a flexible-bandwidth scenario in next-generationmobile communications. Therefore, it is urgent to provide a channellistening mechanism applicable to a flexible-bandwidth scenario toimprove communication efficiency.

SUMMARY

This application provides a communication method and a transmit enddevice, to implement channel listening in a flexible-bandwidth scenario,so as to improve communication efficiency.

A first aspect of this application provides a communication method,including: after a first transmit end device obtains a first bandwidthusable within a first specified time period from an unlicensed frequencyband through contention and completes first service transmission in thefirst specified time period, in respect of at least one second servicetransmission started in a remaining time period of the first specifiedtime period, comparing, by a second transmit end device, magnitudes of asecond bandwidth carrying the second service transmission and the firstbandwidth; using, by the second transmit end device, a correspondingchannel listening mechanism based on a result of the comparison toperform channel listening on the second bandwidth; and performing, bythe second transmit end device, the second service transmission on thesecond bandwidth if the second bandwidth is found to be in an idlestate. This application discloses a channel listening mechanismapplicable to a flexible-bandwidth scenario is disclosed. Correspondingchannel listening mechanisms may be used depending on differentbandwidths, thereby improving communication efficiency.

In an embodiment, the using, by the second transmit end device, acorresponding channel listening mechanism based on a result of thecomparison to perform channel listening on the second bandwidthincludes: if the result of the comparison is that the second bandwidthis less than or equal to the first bandwidth, performing, by the secondtransmit end device, listening by using a non-random backoff basedchannel listening mechanism to determine whether the second bandwidth isin an idle state. In this embodiment, channel listening may beimplemented quickly by using the non-random backoff based channellistening mechanism.

In another embodiment, the method further includes: in respect of the atleast one second service transmission started in the remaining timeperiod of the first specified time period, comparing, by the secondtransmit end device, whether the second bandwidth carrying the secondservice transmission is less than or equal to a third bandwidth carryinglast discontinuous second service transmission preceding the secondservice transmission; if a result of the comparison is that the secondbandwidth is less than or equal to the third bandwidth, performing, bythe second transmit end device, listening by using a non-random backoffbased channel listening mechanism to determine whether the secondbandwidth is in an idle state; and performing, by the second transmitend device, the second service transmission on the second bandwidth ifthe second bandwidth is found to be in an idle state. In thisembodiment, when the second bandwidth is less than or equal to the thirdbandwidth carrying last discontinuous second service transmissionpreceding the second service transmission, channel listening may beperformed by using the non-random backoff based channel listeningmechanism. In this way, channel listening in a flexible-bandwidthscenario can be flexibly and efficiently implemented.

In still another embodiment, the first specified time period is a firstmaximum channel occupancy time MCOT obtained by the first transmit enddevice on the first bandwidth, where the first MCOT includes a sum oftransmission time periods of all service transmission started on thefirst bandwidth, or the first MCOT includes a sum of transmission timeperiods of all service transmission started on the first bandwidth andtime intervals of all discontinuous service transmission, or the firstMCOT includes a sum of transmission time periods of all servicetransmission started on the first bandwidth and a time interval ofdiscontinuous service transmission satisfying a specified condition. Inthis embodiment, an effective channel occupancy time of the firsttransmit end device on the first bandwidth is specified. If theeffective time expires, listening on the first bandwidth needs to beperformed again by using a random backoff based channel listeningmechanism to obtain a new effective channel occupancy time.

In still another embodiment, the using, by the second transmit enddevice, a corresponding channel listening mechanism based on a result ofthe comparison to perform channel listening on the second bandwidthincludes: if the result of the comparison is that the second bandwidthis greater than the first bandwidth, performing, by the second transmitend device, listening by using a random backoff based channel listeningmechanism to determine whether the second bandwidth is in an idle state;and the performing, by the second transmit end device, the secondservice transmission on the second bandwidth if the second bandwidth isfound to be in an idle state includes: performing, by the secondtransmit end device, the second service transmission on the secondbandwidth in a second specified time period if the second bandwidth isfound to be in an idle state, where the second specified time period isa second MCOT obtained by the second transmit end device on the secondbandwidth, where the second MCOT includes a sum of transmission timeperiods of all service transmission started on the second bandwidth, orthe second MCOT includes a sum of transmission time periods of allservice transmission started on the second bandwidth and time intervalsof all discontinuous service transmission, or the second MCOT includes asum of transmission time periods of all service transmission started onthe second bandwidth and a time interval of discontinuous servicetransmission satisfying a specified condition. In this embodiment, whenthe second bandwidth is greater than the first bandwidth, listening onthe second bandwidth needs to be performed by using the random backoffbased channel listening mechanism.

In still another embodiment, the method further includes: if the resultof the comparison is that the second bandwidth is greater than the firstbandwidth, performing, by the second transmit end device, listening byusing a non-random backoff based channel listening mechanism todetermine whether the first bandwidth is in an idle state, andperforming listening by using a random backoff based channel listeningmechanism to determine whether a remainder fourth bandwidth is in anidle state, where the fourth bandwidth is a difference between thesecond bandwidth and the first bandwidth; and performing, by the secondtransmit end device, the second service transmission on the secondbandwidth if both the first bandwidth and the fourth bandwidth are foundto be in an idle state. In this embodiment, when the second bandwidth isgreater than the first bandwidth, listening may be performed by usingthe non-random backoff based channel listening mechanism to determinewhether the first bandwidth is in an idle state, and listening may beperformed by using the random backoff based channel listening mechanismto determine whether the remainder fourth bandwidth is in an idle state.In this way, channel listening in a flexible-bandwidth scenario can beflexibly and efficiently implemented.

In still another embodiment, the first service transmission includes atleast one of the following types: uplink service transmission anddownlink service transmission; and the plurality of times ofdiscontinuous second service transmission include at least one of thefollowing types: uplink service transmission and downlink servicetransmission.

In still another embodiment, a length of a contention window of therandom backoff based channel listening mechanism is fixed or variable.

Another aspect of this application provides a transmit end device. Thetransmit end device has a function of implementing actions of thetransmit end device in the foregoing method. The function may beimplemented by hardware, or may be implemented by hardware by executingcorresponding software. The hardware or software includes one or moremodules corresponding to the foregoing function.

In a embodiment, the transmit end device includes: a comparison unit,configured to: after a first transmit end device obtains a firstbandwidth usable within a first specified time period from an unlicensedfrequency band through contention and completes first servicetransmission in the first specified time period, in respect of at leastone second service transmission started in the remaining time period ofthe first specified time period, compare magnitudes of a secondbandwidth carrying the second service transmission and the firstbandwidth; a listening unit, configured to use a corresponding channellistening mechanism based on a comparison result of the comparison unitto perform channel listening on the second bandwidth; and a transmissionunit, configured to perform the second service transmission on thesecond bandwidth if the listening unit finds that the second bandwidthis in an idle state.

In another embodiment, the transmit end device includes a receiver, atransmitter, a memory, and a processor. The memory stores a group ofprogram code, and the processor is configured to invoke the program codestored in the memory to perform the following operations: after a firsttransmit end device obtains a first bandwidth usable within a firstspecified time period from an unlicensed frequency band throughcontention and completes first service transmission in the firstspecified time period, in respect of at least one second servicetransmission started in the remaining time period of the first specifiedtime period, comparing magnitudes of a second bandwidth carrying thesecond service transmission and the first bandwidth; using acorresponding channel listening mechanism based on a result of thecomparison to perform channel listening on the second bandwidth; andperforming, by the second transmit end device, the second servicetransmission on the second bandwidth if the second bandwidth is found tobe in an idle state.

Based on a same disclosure idea, for a principle for resolving a problemby the apparatus and beneficial effects of the apparatus, reference maybe made to each embodiment of the method performed by the foregoingtransmit end device and beneficial effects brought by them. Therefore,for implementation of the apparatus, refer to implementation of themethod, and repeated content is not described herein again.

Still another aspect of this application provides a computer-readablestorage medium. The computer-readable storage medium stores aninstruction, and when the instruction is run on a computer, the computeris enabled to perform the methods described in the foregoing aspects.

Still another aspect of this application provides a computer programproduct including an instruction. When the instruction is run on acomputer, the computer is enabled to perform the methods described inthe foregoing aspects.

BRIEF DESCRIPTION OF DRAWINGS

To describe the technical solutions in embodiments of the presentdisclosure or in the background more clearly, the following describesaccompanying drawings required for describing the embodiments of thepresent disclosure or the background.

FIG. 1 is a schematic architectural diagram of a communications systemaccording to an embodiment of the present disclosure;

FIG. 2 is a schematic flowchart of a communication method according toan embodiment of the present disclosure;

FIG. 3 is a schematic flowchart of a further detailed embodiment of thecommunication method provided in FIG. 2 ;

FIG. 4 is a schematic diagram of an example of channel listening;

FIG. 5A is a schematic diagram of another example of channel listening;

FIG. 5B is a schematic diagram of still another example of channellistening;

FIG. 6 is a schematic flowchart of another further detailed embodimentof the communication method provided in FIG. 2 ;

FIG. 7 is a schematic diagram of still another example of channellistening;

FIG. 8 is a schematic flowchart of another communication methodaccording to an embodiment of the present disclosure;

FIG. 9 is a schematic diagram of still another example of channellistening;

FIG. 10 is a schematic module diagram of a transmit end device accordingto an embodiment of the present disclosure; and

FIG. 11 is a schematic structural diagram of hardware of a transmit enddevice according to an embodiment of the present disclosure.

DESCRIPTION OF EMBODIMENTS

The following describes the embodiments of the present disclosure withreference to the accompanying drawings in the embodiments of the presentdisclosure.

FIG. 1 is a schematic architectural diagram of a communications systemaccording to an embodiment of the present disclosure. The communicationssystem includes a base station and a terminal device. The communicationssystem may be a global system for mobile communications (GSM), a codedivision multiple access (CDMA) system, a wideband code divisionmultiple access (WCDMA) system, a worldwide interoperability formicrowave access (WiMAX) system, a long term evolution (LTE) system, a5G communications system (for example, a new radio (NR) system), acommunications system integrating a plurality of communicationstechnologies (for example, a communications system integrating an LTEtechnology and an NR technology), or a subsequent evolved communicationssystem.

The terminal device in this application is a device having a wirelesscommunication function, and may be a handheld device, a vehicle-mounteddevice, a wearable device, or a computing device that has a wirelesscommunication function, or another processing device connected to awireless modem, or the like. Terminal devices in different networks mayhave different names. For example, the terminal device may be referredto as a user equipment (UE), an access terminal, a subscriber unit, asubscriber station, a mobile station, a mobile console, a remotestation, a remote terminal, a mobile device, a user terminal, aterminal, a wireless communications device, a user agent or a userapparatus, a cellular phone, a cordless telephone set, a sessioninitiation protocol (SIP) phone, a wireless local loop (WLL) station, apersonal digital assistant (PDA), and a terminal device in a 5G networkor a future evolved network.

The network device in this application is a device deployed in a radioaccess network to provide a wireless communication function, and thenetwork device includes but is not limited to a base station (forexample, a BTS, a NodeB (NB), an evolved NodeB (eNB or eNodeB), atransmission node in an NR system or a transmission reception point (TRPor TP), or a next-generation NodeB (gNB), and a base station or anetwork device in a future communications network), a relay node, anaccess point, a vehicle-mounted device, a wearable device, a wirelessfidelity (Wi-Fi) site, a wireless backhaul node, a small cell, and amicro cell.

Specifically, in FIG. 1 , a base station 102 may include a plurality ofantenna groups. Each antenna group may include one or more antennas, forexample, one antenna group may include antennas 104 and 106, and anotherantenna group may include antennas 108 and 110. In addition, anadditional group may be included, and the additional group may includeantennas 112 and 114. In high frequency communication, different antennagroups may constitute different antenna panels. For example, one antennagroup forms a beam pointing to one direction, and another antenna groupforms another beam pointing to another direction. To adapt to differentdevice capabilities, more antennas may be required. Therefore, dependingon different device capabilities, the additional groups may be providedwith different quantities of antennas. For example, FIG. 1 shows a casein which each antenna group includes two antennas. However, there may bemore or fewer antennas in each group. The base station 102 mayadditionally include a transmitter chain and a receiver chain. A personof ordinary skill in the art may understand that the transmitter chainand the receiver chain each may include a plurality of componentsrelated to signal transmission and reception, for example, a processor,a modulator, a multiplexer, a demodulator, a demultiplexer, or anantenna.

The base station 102 may communicate with one or more terminal devices,for example, a terminal device 116 and a terminal device 122. However,it may be understood that the base station 102 may communicate with anyquantity of terminal devices similar to the terminal device 116 or 122.As shown in FIG. 1 , the terminal device 116 communicates with theantennas 112 and 114, where the antennas 112 and 114 send information tothe terminal device 116 through a forward link 118, and receiveinformation from the terminal device 116 through a reverse link 120. Inaddition, the terminal device 122 communicates with the antennas 104 and106, where the antennas 104 and 106 send information to the terminaldevice 122 through a forward link 124, and receive information from theterminal device 122 through a reverse link 126. In a frequency divisionduplex (FDD) system, for example, a frequency band used on the forwardlink 118 may be different from that used on the reverse link 120, and afrequency band used on the forward link 124 may be different from thatused on the reverse link 126. In addition, in a time division duplex(TDD) system, a frequency band used on the forward link 118 may be thesame as that used on the reverse link 120, and a frequency band used onthe forward link 124 may be the same as that used on the reverse link126.

A coverage area and/or transmission area of each group of antennas thatare/is designed for communication are/is referred to as a sector of thebase station 102. For example, an antenna group may be designed tocommunicate with a terminal device in a sector, namely, a coverage area,of the base station 102. When the base station 102 communicates withterminal devices 116 and 122 through the forward links 118 and 124respectively, transmit antennas of the base station 102 can increasesignal-to-noise ratios of the forward links 118 and 124 throughbeamforming. In addition, compared with a manner in which the basestation 102 uses a single antenna to send a signal to all accessterminal devices served by the base station, in a manner in which thebase station 102 sends, through beamforming, a signal to the terminaldevices 116 and 122 randomly scattered in a related coverage area, amobile node in a neighboring cell receives less interference.

Within a given time period, the base station 102, the terminal device116, or the terminal device 122 may be a wireless communicationstransmission device and/or a wireless communications receiving device.When sending data, the wireless communications transmission device mayencode the data for transmission. For example, the wirelesscommunications transmission device may obtain, for example, bygenerating, by receiving from another communications device, or bystoring in a memory, a specific quantity of data bits to be transmittedto a wireless communications receiving device through a channel. Suchdata bits may be included in one or more transmission blocks of thedata, and the transmission block may be segmented to generate aplurality of code blocks.

The embodiments of the present disclosure provide a communication methodand a transmit end device. A first transmit end device obtains a firstbandwidth usable within a specified time period through contention, andin respect of at least one second service transmission started in theremaining time period of the specified time period, a second transmitend device compares magnitudes of a second bandwidth carrying the secondservice transmission and the first bandwidth, and uses a correspondingchannel listening mechanism based on a result of the comparison toperform channel listening on the second bandwidth, to perform the secondservice transmission. In this way, corresponding channel listeningmechanisms may be used depending on different bandwidths, therebyimproving communication efficiency.

In the embodiments of the present disclosure, the transmit end devicemay be a network device or a terminal device. In other words, if anetwork device transmits a beam on an unlicensed frequency band, thenetwork device performs channel listening; or if a terminal devicetransmits a beam on an unlicensed frequency band, the terminal deviceperforms channel listening.

In different communications systems, channel listening may havedifferent names, for example, in the 3rd generation partnership project(3GPP) or in 5th generation mobile communications, channel listening isreferred to as listen before talk (LBT). LBT means that a node thatneeds to transmit data first performs listening to determine whetherthere is a carrier or a signal on a medium to determine whether anothernode is transmitting data. If the medium is idle, the node can transmitdata; or if the medium is not idle, the node performs backoff basedchannel listening again. For another example, in Wi-Fi communication,channel listening is implemented through clear channel assessment (CCA).CCA means that to effectively avoid a collision, a node must be able toaccurately determine whether a channel is idle, when signal powerreceived on the channel exceeds a specific threshold, it is consideredthat another node is performing communication on the listened channel.In this case, the node does not perform communication, so as to avoidinterference and a collision, and avoid a case in which datatransmission reliability and data transmission efficiency cannot beensured.

For different application scenarios, the foregoing channel listeningmechanisms may include four categories: Cat 1: no channel listening anddetection is performed before data transmission; Cat 2: no randombackoff based channel listening mechanism is performed; Cat 3: a randombackoff based channel listening mechanism with a fixed contentionwindow; and Cat 4: a random backoff based channel listening mechanismwith a variable contention window. The foregoing four channel listeningmechanisms are used as examples for description. A channel listeningmechanism used in the embodiments of the present disclosure is notlimited thereto.

The communication method provided in the embodiments of this applicationis applicable to both types of communication. The following first usesLBT as an example for description.

FIG. 2 is a schematic flowchart of a communication method according toan embodiment of the present disclosure. The method may include thefollowing steps:

S101. After a first transmit end device obtains a first bandwidth usablewithin a first specified time period from an unlicensed frequency bandthrough contention and completes first service transmission in the firstspecified time period, in respect of at least one second servicetransmission started in a remaining time period of the first specifiedtime period, a second transmit end device compares magnitudes of asecond bandwidth carrying the second service transmission and the firstbandwidth.

In this embodiment, the transmit end device may use bandwidths ofdifferent magnitudes for service transmission depending on servicerequirements. For service transmission in an unlicensed frequency band,channel listening needs to be performed before the service transmission.

The first transmit end device may use a non-random backoff based channellistening mechanism. The non-random backoff based channel listeningmechanism is a fast channel listening mechanism. In other words, beforeperforming transmission, the transmit end device ensures that in aspecified time period (for example, 25 μs), a corresponding channel isidle, namely, the channel is not occupied. In Wi-Fi and 3GPPcommunications systems, a non-random backoff based listening mechanismsimilar to this type is referred to as “Cat. 2”.

The first transmit end device may use a random backoff based channellistening mechanism. The random backoff based channel listeningmechanism includes two types: a first type of random backoff basedchannel listening mechanism is a type of random backoff based listeningmechanism with a fixed contention window (referred to as “type-1 randombackoff” below for short), and in Wi-Fi and 3GPP communications systems,a random backoff based listening mechanism similar to this type isreferred to as “Cat. 3”; and a second type of random backoff basedchannel listening mechanism is a random backoff based listeningmechanism with a variable contention window (referred to as “type-2random backoff” below for short), and in Wi-Fi and 3GPP communicationssystems, a random backoff based listening mechanism similar to this typeis referred to as “Cat. 4”. It should be noted that, the foregoing “Cat.3” and “Cat. 4” are merely used as examples for description for ease ofunderstanding and are not intended to limit a random backoff basedchannel listening mechanism in this embodiment.

The following first describes the type 2 random backoff in detail.Specifically, a transmit end device first needs to ensure that adetected channel is idle within a delay time T_(d), and then starts toperform random backoff. After the backoff is ended, the transmit enddevice accesses the channel and obtains a corresponding channeloccupancy time, namely, a first specified time period. Particularly, ifa transmit end device successfully obtains a spectrum resource throughthe type 2 random backoff LBT, and there is still a remaining timeperiod in the first specified time period after first servicetransmission is completed on a corresponding spectrum, the transmit enddevice may share an occupied channel to another transmit end device forsecond service transmission in the remaining time period of the firstspecified time period. For example, there may be one or more othertransmit end devices, and the second service transmission may includeone service or a plurality of discontinuous services. In other words, ifthere is still a remaining time period in the first specified timeperiod after the first service transmission is completed, at least onesecond service transmission may be started; and if the remaining timeperiod is sufficient, a plurality of times of second servicetransmission may be performed. In this embodiment of the presentdisclosure, the first specified time period is a maximum channeloccupancy time (MCOT) obtained by the first transmit end device on thefirst bandwidth. For example, to define the MCOT, one way is that theMCOT includes a sum of transmission time periods of all servicetransmission started on the first bandwidth (namely, time intervalsbetween discontinuous service transmission are not included in theMCOT); another way is that the MCOT includes a sum of transmission timeperiods of all service transmission started on the first bandwidth andall time intervals between discontinuous transmissions; and a third wayis that the MCOT includes a sum of transmission time periods of allservice transmission started on the first bandwidth and sometransmission time intervals (namely, a transmission interval satisfyinga specified condition is included in the MCOT, for example, a timeinterval less than or greater than a threshold, or a time intervalbetween discontinuous transmissions initiated by one transmit enddevice).

It should be noted that the first service transmission may be uplinkservice transmission or downlink service transmission, in other words,the first transmit end device may be a network device or a terminaldevice, and the second service transmission may also be uplink servicetransmission or downlink service transmission, and if the first transmitend device is a network device, the second service transmission may bedownlink transmission of the first transmit end device, or may be uplinktransmission of a terminal device served by the first transmit enddevice.

Therefore, after the first transmit end device obtains the firstbandwidth usable within the first specified time period throughcontention and completes current service transmission of the firsttransmit end device (the first transmit end device obtains the firstbandwidth through contention to perform the current servicetransmission) by using the first bandwidth in the first specified timeperiod, if next service transmission needs to be performed, channellistening needs to be performed to obtain a resource. Usually, the nextservice transmission and the current service transmission arediscontinuous. In an application scenario of flexible-bandwidthcommunication in an unlicensed frequency band, when the first transmitend device allows another transmit end device to perform second servicetransmission in the remaining time period of the first specified timeperiod on a channel occupied by the first transmit end device, to ensurethat any transmit end device can fairly contend for and efficiently use,in the remaining time period of the first specified time period, theshared channel provided by the first transmit end device, magnitudes ofthe second bandwidth occupied by the next service transmission and thefirst bandwidth need to be compared, so as to select a channel listeningmechanism used before the second service transmission.

S102. The second transmit end device uses a corresponding channellistening mechanism based on a result of the comparison to performchannel listening on the second bandwidth.

When the result of the comparison is that the second bandwidth is lessthan or equal to the first bandwidth (or may be that the secondbandwidth is less than the first bandwidth), because before the secondservice transmission, the first transmit end device has obtained thefirst bandwidth usable within the first specified time period throughcontention, and channel listening for the second service transmission isstarted in the remaining time period of the first specified time periodafter the first service transmission is completed, if the secondbandwidth is less than or equal to the first bandwidth (or the secondbandwidth is less than the first bandwidth), only fast channel listeningneeds to be performed for the second service transmission to beperformed on the second bandwidth. For example, a non-random backoffbased channel listening mechanism is used. In other words, beforeperforming transmission, the transmit end device needs to ensure that acorresponding spectrum is idle, namely, the spectrum is not occupied, ina specified time period (for example, 25 μs). This mechanism is similarto the “Cat. 2 LBT” mechanism in Wi-Fi and 3GPP communications systems.

When the second bandwidth is greater than the first bandwidth (orcorrespondingly, when the second bandwidth is greater than or equal tothe first bandwidth), because the first transmit end device has notobtained a resource of a part, greater than the first bandwidth, in thesecond bandwidth through contention, a random backoff based channellistening mechanism may be used for channel listening, or a combinationof a non-random backoff based channel listening mechanism and a randombackoff based channel listening mechanism is used for channel listening.

S103. The second transmit end device performs the second servicetransmission on the second bandwidth if the second bandwidth is found tobe in an idle state.

The second transmit end device can perform the second servicetransmission on the second bandwidth only when the second bandwidth isfound to be in an idle state.

To sum up, in this embodiment, a corresponding channel listeningmechanism may be used for a channel with a flexible bandwidth, therebyensuring channel listening efficiency and reliability.

According to a channel listening method provided in this embodiment ofthe present disclosure, the first transmit end device obtains the firstbandwidth usable within the specified time period through contention,and in respect of at least one second service transmission started inthe remaining time period of the specified time period, the secondtransmit end device compares magnitudes of the second bandwidth carryingthe second service transmission and the first bandwidth, and uses acorresponding channel listening mechanism based on a result of thecomparison to perform channel listening on the second bandwidth, toperform the second service transmission. In this way, correspondingchannel listening mechanisms may be used depending on differentbandwidths, thereby improving communication efficiency.

FIG. 3 is a schematic flowchart of a further detailed embodiment of achannel listening method provided in FIG. 2 . The method may include thefollowing steps:

S201. A second transmit end device compares whether a second bandwidthcarrying second service transmission is less than or equal to a firstbandwidth; and if the second bandwidth is less than or equal to thefirst bandwidth, perform step S202; or if the second bandwidth isgreater than the first bandwidth, perform step S204.

S202. If a result of the comparison is that the second bandwidth is lessthan or equal to the first bandwidth, the second transmit end deviceperforms listening by using a non-random backoff based channel listeningmechanism to determine whether the second bandwidth is in an idle state.

S203. The second transmit end device performs the second servicetransmission on the second bandwidth if the second bandwidth is found tobe in an idle state.

A network device successfully obtains a spectrum resource on the firstbandwidth, obtains a corresponding MCOT, and performs transmission onthe first bandwidth. If there is still a remaining time period in theMCOT after current transmission is ended, channel listening for thesecond service transmission may be started in the remaining time period.In this way, at least one service transmission (uplink transmission ordownlink transmission) may be performed in the MCOT. For any new servicetransmission, if a corresponding second bandwidth is not greater than afirst bandwidth, the transmit end device may use a non-random backoffbased channel listening mechanism (for example, detecting whether aspectrum is idle within 25 μs) before performing transmission. Ifdetecting that the corresponding spectrum on the second bandwidth isidle, the transmit end device may send a signal; or if detecting thatthe corresponding spectrum on the second bandwidth is not idle, thetransmit end device cannot send a signal.

For example, FIG. 4 is a schematic diagram of an example of channellistening. A network device detects that a spectrum on a first bandwidthBW is idle, obtains a corresponding MCOT, and starts to perform firstservice transmission at a moment T0. For subsequent transmission (uplinkor downlink transmission), if a bandwidth is less than or equal to theBW, and the transmission is performed within a time interval between themoment T0 and a moment T0+MCOT (Herein, it is considered that thetransmission time interval included in the MCOT is a sum of a timeinterval between downlink transmission of the network device and uplinktransmission of UE scheduled by the network device, and a time intervalbetween two times of discontinuous uplink transmission scheduled by thenetwork device, but any time interval between two times of discontinuousdownlink transmission is not included in the transmission timeinterval), before performing subsequent transmission, a transmit enddevice needs to use a non-random backoff based channel listeningmechanism to detect whether a spectrum on the corresponding transmissionbandwidth is idle. If the spectrum is idle, the transmit end devicesends a signal; or if the spectrum is not idle, the transmit end devicecannot send a signal.

S204. If a result of the comparison is that the second bandwidth isgreater than the first bandwidth, the second transmit end deviceperforms listening by using a random backoff based channel listeningmechanism to determine whether the second bandwidth is in an idle state.

S205. The second transmit end device performs the second servicetransmission on the second bandwidth in a second specified time periodif the second bandwidth is found to be in an idle state, where thesecond specified time period is a second MCOT obtained by the secondtransmit end device on the second bandwidth, where the second MCOTincludes a sum of transmission time periods of all service transmissionstarted on the second bandwidth, or the second MCOT includes a sum oftransmission time periods of all service transmission started on thesecond bandwidth and time intervals of all discontinuous servicetransmission, or the second MCOT includes a sum of transmission timeperiods of all service transmission started on the second bandwidth anda time interval of discontinuous service transmission satisfying aspecified condition.

In an embodiment, a scenario of channel listening is that after anetwork device obtains a channel through contention, the network devicemay share the channel for subsequent uplink or downlink transmission ina remaining time period of an MCOT because the network device is morecompetitive. The network device obtains a spectrum resource on a firstbandwidth, obtains a corresponding MCOT, and performs transmission onthe first bandwidth. If a plurality of times of discontinuoustransmission (uplink or downlink transmission) are started in theremaining time period of the MCOT after current transmission iscompleted, for any new transmission, if a corresponding second bandwidthis greater than a first bandwidth, a transmit end device needs toperform random backoff based LBT before performing transmission. Aftersuccessfully performing random backoff based LBT, the transmit enddevice obtains a new MCOT, and in this case, the previous MCOT becomesinvalid.

For example, FIG. 5A shows a schematic diagram of another example ofchannel listening, a network device detects that a spectrum on abandwidth BW is idle, obtains an MCOT, and starts to perform downlinktransmission at a moment T0. After the downlink transmission iscompleted, if a bandwidth used for subsequent transmission (uplinktransmission or downlink transmission) is greater than the BW, beforesending a signal, a transmit end device needs to use a random backoffbased channel listening mechanism to detect whether a spectrum on thecorresponding transmission bandwidth is idle. If the spectrum is idle,the transmit end device obtains a second specified time period (namely,a new MCOT in the figure) and starts to send a signal; or if thespectrum is not idle, the transmit end device cannot send a signal.

In this embodiment, when the second bandwidth is less than or equal tothe first bandwidth, a fast non-random backoff based channel listeningmechanism is used. In this way, channel listening efficiency is improvedand service transmission can be quickly performed. When the secondbandwidth is greater than the first bandwidth, a random backoff basedchannel listening mechanism needs to be used to perform channelcontention again, so as to ensure channel transmission reliability.

In another embodiment, a scenario of channel listening is that afterobtaining a channel through contention, a terminal device usually sharesthe channel for subsequent uplink transmission in a remaining timeperiod of T0+MCOT. The terminal device successfully obtains a spectrumresource on a first bandwidth, obtains a corresponding MCOT, andperforms transmission on the first bandwidth according to aninstruction. If one or more times of uplink transmission are started inthe remaining time period of the MCOT after current transmission iscompleted, for any new subsequent service transmission, if acorresponding second bandwidth is not greater than the first bandwidth,before performing transmission, the terminal device may use a non-randombackoff based LBT to detect whether a spectrum on the second bandwidthis idle; or if the corresponding second bandwidth is greater than thefirst bandwidth, the terminal device needs to perform Cat 4 LBTdetection. After successfully performing Cat 4 LBT detection, theterminal device obtains a new MCOT, and in this case, the previous MCOTbecomes invalid.

For example, FIG. 5B is a schematic diagram of still another example ofchannel listening, a terminal device detects that a spectrum on abandwidth BW is idle, obtains a corresponding MCOT, and starts toperform uplink transmission at a moment T0. For subsequent newtransmission started in a time interval between the moment T0 and amoment T0+MCOT (Herein, it is considered that the transmission timeinterval included in the MCOT is a sum of time intervals between twotimes of adjacent discontinuous uplink transmission), if a transmissionbandwidth is not greater than the BW, before sending a signal, theterminal device needs to perform non-random backoff based LBT to detectwhether a spectrum on the corresponding transmission bandwidth is idle.If the spectrum is idle, the terminal device may send a signal; or ifthe spectrum is not idle, the terminal device cannot send a signal. Onthe contrary, if the transmission bandwidth is greater than the BW,before sending a signal, the terminal device needs to perform randombackoff based LBT to detect whether the spectrum on the correspondingtransmission bandwidth is idle. If the spectrum is idle, the terminaldevice obtains a second specified time period (namely, a new MCOT in thefigure) and starts to send a signal; or if the spectrum is not idle, theterminal device cannot send a signal.

In this embodiment, when the second bandwidth is less than or equal tothe first bandwidth, a fast non-random backoff based channel listeningmechanism is used. In this way, channel listening efficiency is improvedand service transmission can be quickly performed. When the secondbandwidth is greater than the first bandwidth, a random backoff basedchannel listening mechanism needs to be used to perform channelcontention again, so as to ensure channel transmission reliability.

According to a channel listening method provided in this embodiment ofthe present disclosure, a first transmit end device obtains a firstbandwidth usable within the specified time period through contention,and in respect of at least one second service transmission started inthe remaining time period of the specified time period, the secondtransmit end device compares magnitudes of a second bandwidth carryingthe second service transmission and the first bandwidth. When the secondbandwidth is less than or equal to the first bandwidth, the secondtransmit end device uses a fast non-random backoff based channellistening mechanism, so as to improve channel listening efficiency andquickly perform service transmission. When the second bandwidth isgreater than the first bandwidth, the second transmit end device uses arandom backoff based channel listening mechanism to perform channelcontention again, so as to ensure channel transmission reliability. Inthis way, corresponding channel listening mechanisms may be useddepending on different bandwidths, thereby improving communicationefficiency.

FIG. 6 is a schematic flowchart of another further detailed embodimentof a channel listening method provided in FIG. 2 . The method mayinclude the following steps:

S301. A second transmit end device compares whether a second bandwidthcarrying second service transmission is less than or equal to a firstbandwidth; and if the second bandwidth is less than or equal to thefirst bandwidth, perform step S302; or if the second bandwidth isgreater than the first bandwidth, perform step S304.

S302. If a result of the comparison is that the second bandwidth is lessthan or equal to the first bandwidth, the second transmit end deviceperforms listening by using a non-random backoff based channel listeningmechanism to determine whether the second bandwidth is in an idle state.

S303. The second transmit end device performs the second servicetransmission on the second bandwidth if the second bandwidth is found tobe in an idle state.

For an embodiment process of steps S301 to S303, refer to steps S201 andS203 of the embodiment shown in FIG. 3 . Details are not describedherein again.

S304. If the result of the comparison is that the second bandwidth isgreater than the first bandwidth, the second transmit end deviceperforms listening by using a non-random backoff based channel listeningmechanism to determine whether the first bandwidth is in an idle state,and performs listening by using a random backoff based channel listeningmechanism to determine whether a remainder fourth bandwidth is in anidle state, where the fourth bandwidth is a difference between thesecond bandwidth and the first bandwidth.

S305. The second transmit end device performs the second servicetransmission on the second bandwidth if both the first bandwidth and thefourth bandwidth are found to be in an idle state.

Assuming that a network device successfully obtains a spectrum resourceon a first bandwidth, obtains a corresponding MCOT, and performstransmission on the first bandwidth, if one or more times of servicetransmission (uplink or downlink transmission) are started in theremaining time period of the MCOT after current transmission is ended,for each subsequent new transmission, if a corresponding secondbandwidth is greater than the first bandwidth, before performingtransmission, the device may perform non-random backoff based LBT on thefirst bandwidth to detect whether a spectrum is idle, and may perform arandom backoff based LBT on a remainder fourth bandwidth (a differenceobtained by subtracting the first bandwidth from the second bandwidth)to detect whether the corresponding spectrum is idle. Before acorresponding sending moment, if detecting that both the spectra on thefirst bandwidth and the fourth bandwidth are idle, the device may send asignal; or if detecting that neither of the spectra is idle or any ofthe spectra is idle, the device cannot send a signal.

For example, FIG. 7 is a schematic diagram of still another example ofchannel listening, a network device detects that a spectrum on abandwidth BW is idle, obtains a corresponding MCOT, and starts toperform downlink transmission at a moment T0. For subsequent newdownlink transmission, if a transmission bandwidth BW′ is greater thanBW, the transmission is performed within the time interval between themoment T0 and a moment T0+MCOT, and preceding transmission nearest tothe new downlink transmission is uplink transmission, before sending asignal, a transmit end device needs to perform non-random backoff basedLBT to detect whether a spectrum on the corresponding bandwidth BW isidle, and perform random backoff based LBT to detect whether a spectrumon a bandwidth (BW′-BW) is idle. If finally detecting that the spectraon the two bandwidths are idle, the transmit end device sends a signal;or if finally detecting that neither of the spectra is idle or any ofthe spectra is idle, the transmit end device cannot send a signal.

It should be noted that in this embodiment, new transmission andpreceding transmission nearest to the new transmission need to betransmission performed in different directions. In other words, if thenew transmission is downlink transmission, the preceding transmissionnearest to the new transmission should be uplink transmission; andsimilarly, if the new transmission is uplink transmission, the precedingtransmission nearest to the new transmission should be downlinktransmission. This is because only in this way, there is enough time toperform random backoff based LBT before the new service transmission isstarted.

According to the communication method provided in this embodiment of thepresent disclosure, a first transmit end device obtains a firstbandwidth usable within a specified time period through contention, andin respect of at least one second service transmission started in theremaining time period of the specified time period, the second transmitend device compares magnitudes of a second bandwidth carrying the secondservice transmission and the first bandwidth. When the second bandwidthis less than or equal to the first bandwidth, the second transmit enddevice uses a fast non-random backoff based channel listening mechanism,so as to improve channel listening efficiency and quickly performservice transmission. When the second bandwidth is greater than thefirst bandwidth, the second transmit end device uses a random backoffbased channel listening mechanism to perform channel contention again,so as to ensure channel transmission reliability. In this way,corresponding channel listening mechanisms may be used depending ondifferent bandwidths, thereby improving communication efficiency.

FIG. 8 is a schematic flowchart of another communication methodaccording to an embodiment of the present disclosure. The method mayinclude the following steps:

S401. In respect of at least one second service transmission started ina remaining time period of a first specified time period, the secondtransmit end device compares whether a second bandwidth carrying thesecond service transmission is less than or equal to a third bandwidthcarrying last discontinuous second service transmission preceding thesecond service transmission.

S402. If a result of the comparison is that the second bandwidth is lessthan or equal to the third bandwidth, the second transmit end deviceperforms listening by using a non-random backoff based channel listeningmechanism to determine whether the second bandwidth is in an idle state.

S403. The second transmit end device performs the second servicetransmission on the second bandwidth if the second bandwidth is found tobe in an idle state.

A network device successfully obtains a spectrum resource on a firstbandwidth, obtains a corresponding MCOT, and performs transmission onthe first bandwidth. If one or more times of service transmission(uplink or downlink transmission) are started in the remaining timeperiod of the first specified time period after current transmission iscompleted, for each subsequent new transmission, if a correspondingsecond bandwidth is not greater than a third bandwidth carrying lastpreceding transmission that is near to the new transmission, the devicemay perform non-random backoff based LBT (for example, detecting whethera spectrum is idle within 25 μs) before performing transmission. Ifdetecting that the corresponding spectrum on the second bandwidth isidle, the device may send a signal; or if detecting that thecorresponding spectrum on the second bandwidth is not idle, the devicecannot send a signal.

For example, FIG. 9 is a schematic diagram of still another example ofchannel listening. In FIG. 9 , a network device detects that a spectrumon a bandwidth BW is idle, obtains a corresponding MCOT, and starts toperform downlink transmission at a moment T0. For subsequenttransmission (uplink or downlink transmission), if a bandwidth is lessthan or equal to a bandwidth BW′ carrying last preceding transmission,and the transmission is performed within a time interval between themoment T0 and a moment T0+MCOT (Herein, it is considered that thetransmission time interval included in the MCOT includes a sum of a timeinterval between downlink transmission of the network device andadjacent uplink transmission of UE scheduled by the network device, anda time interval between two times of adjacent discontinuous uplinktransmission scheduled by the network device, but any time intervalbetween two times of discontinuous downlink transmission is not includedin Tg), before sending a signal, a transmit end device needs to performnon-random backoff based LBT to detect whether a spectrum on thecorresponding transmission bandwidth is idle. If detecting that thespectrum is idle, the transmit end device sends a signal; or ifdetecting that the spectrum is not idle, the transmit end device cannotsend a signal.

According to the communication method provided in this embodiment of thepresent disclosure, a first transmit end device obtains a firstbandwidth usable within a specified time period through contention, andin respect of at least one second service transmission started in theremaining time period of the specified time period, the second transmitend device compares magnitudes of a second bandwidth carrying the secondservice transmission and the first bandwidth. When the second bandwidthis less than or equal to the first bandwidth, the second transmit enddevice uses a fast non-random backoff based channel listening mechanism,so as to improve channel listening efficiency and quickly performservice transmission. When the second bandwidth is greater than thefirst bandwidth, the second transmit end device uses a random backoffbased channel listening mechanism to perform channel contention again,so as to ensure channel transmission reliability. In this way,corresponding channel listening mechanisms may be used depending ondifferent bandwidths, thereby improving communication efficiency.

The foregoing describes in detail the method in the embodiments of thepresent disclosure. The following provides an apparatus in theembodiments of the present disclosure.

FIG. 10 is a schematic module diagram of a transmit end device accordingto an embodiment of the present disclosure, and the transmit end deviceis applicable to the communications system shown in FIG. 1 . Thetransmit end device 1000 may include a comparison unit 11, a listeningunit 12, and a transmission unit 13. The comparison unit 11 isconfigured to compare magnitudes of a second bandwidth and a firstbandwidth, for example, to perform the foregoing S101 part; thelistening unit 12 is configured to listen to a channel of the secondbandwidth, for example, to perform the foregoing S102 part; and thetransmission unit 13 is configured to communicate with a receive enddevice, for example, to perform the foregoing S103 part; and performsecond service transmission if the second bandwidth is in an idle state.

In an embodiment, the comparison unit 11 may be further configured toperform the foregoing S201 part; the listening unit 12 may be furtherconfigured to perform the foregoing S202 or S204 part; and thetransmission unit 13 may be further configured to perform the foregoingS203 or S205 part.

In another embodiment, the comparison unit 11 may be further configuredto perform the foregoing S301 part; the listening unit 12 may be furtherconfigured to perform the foregoing S302 or S304 part; and thetransmission unit 13 may be further configured to perform the foregoingS303 or S305 part.

In still another embodiment, the comparison unit 11 may be furtherconfigured to perform the foregoing S401 part; the listening unit 12 maybe further configured to perform the foregoing S402 part; and thetransmission unit 13 may be further configured to perform the foregoingS403 part.

For details, refer to the description in the method embodiments. Detailsare not described herein again.

According to the transmit end device provided in this embodiment of thepresent disclosure, corresponding channel listening mechanisms may beused depending on different bandwidths, thereby improving communicationefficiency.

FIG. 11 is a schematic structural diagram of hardware of a transmit enddevice according to an embodiment of the present disclosure, and thetransmit end device is applicable to the communications system shown inFIG. 1 . The transmit end device 2000 may include a transceiver 21, aprocessor 22, and a memory 23. The transceiver 21, the processor 22, andthe memory 23 are connected to each other by using a bus 24. Relatedfunctions implemented by the comparison unit 11 and the listening unit12 in FIG. 10 may be implemented by one or more processors 22. A relatedfunction implemented by the transmission unit 13 in FIG. 10 may beimplemented by the transceiver 21.

The memory 23 includes but is not limited to a random access memory(RAM), a read-only memory (ROM), an erasable programmable read onlymemory (EPROM), or a compact disc read-only memory (CD-ROM). The memory23 is configured to store a related instruction and data.

The transceiver 21 is configured to send data and/or a signal andreceive data and/or a signal.

The processor 22 may include one or more processors, for example, one ormore central processing units (CPUs). When the processor 22 is a CPU,the CPU may be a single-core CPU, or may be a multi-core CPU.

The processor 23 is configured to support the transmit end device inperforming steps S101 and S102 shown in FIG. 2 , that is, comparemagnitudes of a second bandwidth and a first bandwidth and listen to achannel of the second bandwidth. The memory 23 is configured to storeprogram code and data of the transmit end device.

The transceiver 21 is configured to communicate with a receive enddevice, perform step S103 shown in FIG. 2 , and perform second servicetransmission on the second bandwidth if the second bandwidth is in anidle state.

For details about steps performed by the processor 23 and thetransceiver 21, refer to the description in the embodiments shown inFIG. 2 to FIG. 9 . Details are not described herein again.

For details, refer to the description in the method embodiments. Detailsare not described herein again.

It can be understood that FIG. 11 shows merely a simplified design ofthe transmit end device. In actual application, when the transmit enddevice is a base station or a terminal device, the transmit end devicemay further include another necessary component. The component includesbut is not limited to any quantity of transceivers, processors,controllers, memories, and communications unit, and all transmit enddevices that can implement the present disclosure fall within theprotection scope of the present disclosure.

According to the transmit end device provided in this embodiment of thepresent disclosure, corresponding channel listening mechanisms may beused depending on different bandwidths, thereby improving communicationefficiency.

An embodiment of the present disclosure further provides acomputer-readable storage medium. The computer-readable storage mediumstores an instruction, and when the instruction is run on a computer,the computer is enabled to perform the methods described in theforegoing aspects.

An embodiment of the present disclosure further provides a computerprogram product including an instruction. When the instruction is run ona computer, the computer is enabled to perform the methods described inthe foregoing aspects.

A person of ordinary skill in the art may be aware that, in combinationwith the examples described in the embodiments disclosed in thisspecification, units and algorithm steps may be implemented byelectronic hardware or a combination of computer software and electronichardware. Whether the functions are performed by hardware or softwaredepends on particular applications and design constraints of thetechnical solutions. A person skilled in the art may use differentmethods to implement the described functions for each particularapplication, but it should not be considered that the implementationgoes beyond the scope of this application. It may be clearly understoodby a person skilled in the art that, for convenient and briefdescription, for a detailed working process of the foregoing system,apparatus, and unit, refer to a corresponding process in the foregoingmethod embodiments, and details are not described herein again.

In the several embodiments provided in this application, it should beunderstood that the disclosed system, apparatus, and method may beimplemented in other manners. For example, the described apparatusembodiment is merely an example. For example, the unit division ismerely logical function division and may be other division in actualimplementation. For example, a plurality of units or components may becombined or integrated into another system, or some features may beignored or not performed. In addition, the displayed or discussed mutualcouplings or direct couplings or communication connections may beimplemented by using some interfaces. The indirect couplings orcommunication connections between the apparatuses or units may beimplemented in electrical, mechanical, or another form.

The units described as separate parts may or may not be physicallyseparate, and parts displayed as units may or may not be physical units,may be located in one position, or may be distributed on a plurality ofnetwork units. Some or all of the units may be selected based on actualrequirements to achieve the objectives of the solutions of theembodiments.

In addition, functional units in the embodiments of this application maybe integrated into one processing unit, or each of the units may existalone physically, or two or more units are integrated into one unit.

All or some of the foregoing embodiments may be implemented by usingsoftware, hardware, firmware, or any combination thereof. When softwareis used to implement the embodiments, the embodiments may be implementedcompletely or partially in a form of a computer program product. Thecomputer program product includes one or more computer instructions.When the computer program instructions are loaded and executed on thecomputer, the procedure or functions according to the embodiments of thepresent disclosure are all or partially generated. The computer may be ageneral-purpose computer, a dedicated computer, a computer network, oranother programmable apparatus. The computer instruction may be storedin a computer-readable storage medium, or may be transmitted by usingthe computer-readable storage medium. The computer instruction may betransmitted from a website, a computer, a server, or a data center toanother website, computer, server, or data center in a wired (forexample, a coaxial cable, an optical fiber, or a digital subscriber line(DSL)) or wireless (for example, infrared, radio, or microwave) manner.The computer-readable storage medium may be any usable medium accessibleby a computer, or a data storage device, such as a server or a datacenter, integrating one or more usable media. The usable medium may be amagnetic medium (for example, a floppy disk, a hard disk, or a magnetictape), an optical medium (for example, a DVD), a semiconductor medium(for example, a solid-state drive (SSD), or the like.

A person of ordinary skill in the art may understand that all or some ofthe processes of the methods in the embodiments may be implemented by acomputer program instructing relevant hardware. The program may bestored in a computer-readable storage medium. When the program isexecuted, the processes of the method embodiments are performed. Theforegoing storage medium includes various media that can store programcode, such as a ROM, a random access memory RAM, a magnetic disk, or acompact disc.

The invention claimed is:
 1. A communication method, comprising:comparing, by a second transmit end device, a second bandwidth carryingat least one second service transmission and a first bandwidth, whereinthe first bandwidth is used by a first transmit end device within afirst specified time period on an unlicensed frequency band to completea first service transmission, and wherein the at least one secondservice transmission starts in a remaining time period of the firstspecified time period after the first service transmission and ends inthe first specified time period; performing, by the second transmit enddevice, channel listening on the second bandwidth based on a result ofthe comparing; and performing, by the second transmit end device, thesecond service transmission on the second bandwidth based on the secondbandwidth being found to be in an idle state.
 2. The method according toclaim 1, wherein based on the result of the comparing being that thesecond bandwidth is less than or equal to the first bandwidth,performing, by the second transmit end device, listening usingnon-random backoff based channel listening to determine whether thesecond bandwidth is in an idle state.
 3. The method according to claim1, wherein the method further comprises: comparing, by the secondtransmit end device, whether the second bandwidth carrying the secondservice transmission is less than or equal to a third bandwidth carryinga last discontinuous second service transmission preceding the secondservice transmission; in response to determining that a result of thecomparing whether the second bandwidth is less than or equal to thethird bandwidth is that the second bandwidth is less than or equal tothe third bandwidth, performing, by the second transmit end device,listening using non-random backoff based channel listening to determinewhether the second bandwidth is in an idle state; and performing, by thesecond transmit end device, the second service transmission on thesecond bandwidth based on the second bandwidth being found to be in anidle state.
 4. The method according to claim 1, wherein the firstspecified time period is a first maximum channel occupancy time (MCOT)obtained by the first transmit end device on the first bandwidth; andwherein the first MCOT comprises: a sum of transmission time periods ofall service transmissions started on the first bandwidth, or a sum oftransmission time periods of all service transmissions started on thefirst bandwidth and time intervals of all discontinuous servicetransmissions, or a sum of transmission time periods of all servicetransmissions started on the first bandwidth and a time interval of adiscontinuous service transmission satisfying a specified condition. 5.The method according to claim 1, wherein in response to determining thatthe result of the comparing is that the second bandwidth is greater thanthe first bandwidth, performing, by the second transmit end device,listening using random backoff based channel listening to determinewhether the second bandwidth is in an idle state; and performing, by thesecond transmit end device, the second service transmission on thesecond bandwidth in a second specified time period based on the secondbandwidth being found to be in an idle state, wherein the secondspecified time period is a second maximum channel occupancy time (MCOT)obtained by the second transmit end device on the second bandwidth, andwherein the second MCOT comprises: a sum of transmission time periods ofall service transmissions started on the second bandwidth, or a sum oftransmission time periods of all service transmissions started on thesecond bandwidth and time intervals of all discontinuous servicetransmissions, or a sum of transmission time periods of all servicetransmissions started on the second bandwidth and a time interval of adiscontinuous service transmission satisfying a specified condition. 6.The method according to claim 1, wherein the method further comprises:in response to determining that the result of the comparing is that thesecond bandwidth is greater than the first bandwidth, performing, by thesecond transmit end device, listening using non-random backoff basedchannel listening to determine whether the first bandwidth is in an idlestate, and performing listening using random backoff based channellistening to determine whether a remainder fourth bandwidth is in anidle state, wherein the fourth bandwidth is a difference between thesecond bandwidth and the first bandwidth; and performing, by the secondtransmit end device, the second service transmission on the secondbandwidth based on both the first bandwidth and the fourth bandwidthbeing found to be in an idle state.
 7. The method according to claim 1,wherein the first service transmission comprises at least one of thefollowing types: uplink service transmission and downlink servicetransmission; and the plurality of times of discontinuous second servicetransmission comprise at least one of the following types: uplinkservice transmission and downlink service transmission.
 8. The methodaccording to claim 1, wherein a length of a contention window of therandom backoff based channel listening is fixed or variable.
 9. Atransmit end device, comprising a transceiver; and a processor,configured to: compare a second bandwidth carrying at least one secondservice transmission and a first bandwidth, wherein the first bandwidthis used by a first transmit end device within a first specified timeperiod on an unlicensed frequency band to complete a first servicetransmission, and wherein the at least one second service transmissionstarts in a remaining time period of the first specified time periodafter the first service transmission and ends in the first specifiedtime period; perform channel listening on the second bandwidth based ona result of the comparing; and control the transceiver to perform thesecond service transmission on the second bandwidth based on the secondbandwidth being found to be in an idle state.
 10. The transmit enddevice according to claim 9, wherein based on the result of thecomparing being that the second bandwidth is less than or equal to thefirst bandwidth, the processor is configured to perform listening usingnon-random backoff based channel listening to determine whether thesecond bandwidth is in an idle state.
 11. The transmit end deviceaccording to claim 10, wherein the processor is further configured to:compare whether the second bandwidth carrying the second servicetransmission is less than or equal to a third bandwidth carrying a lastdiscontinuous second service transmission preceding the second servicetransmission; in response to determining that a result of the comparingwhether the second bandwidth is less than or equal to the thirdbandwidth is that the second bandwidth is less than or equal to thethird bandwidth, perform listening using non-random backoff basedchannel listening to determine whether the second bandwidth is in anidle state; and control the transceiver to perform the second servicetransmission on the second bandwidth based on the second bandwidth beingfound to be in an idle state.
 12. The transmit end device according toclaim 9, wherein the first specified time period is a first maximumchannel occupancy time (MCOT) obtained by the first transmit end deviceon the first bandwidth; and wherein the first MCOT comprises: a sum oftransmission time periods of all service transmissions started on thefirst bandwidth, or a sum of transmission time periods of all servicetransmissions started on the first bandwidth and time intervals of alldiscontinuous service transmissions, or a sum of transmission timeperiods of all service transmissions started on the first bandwidth anda time interval of a discontinuous service transmission satisfying aspecified condition.
 13. The transmit end device according to claim 9,wherein in response to determining that the result of the comparing isthat the second bandwidth is greater than the first bandwidth, theprocessor is configured to perform listening using random backoff basedchannel listening to determine whether the second bandwidth is in anidle state; and wherein the processor is further configured to controlthe transceiver to perform the second service transmission on the secondbandwidth in a second specified time period based on the secondbandwidth being found to be in an idle state, wherein the secondspecified time period is a second maximum channel occupancy time (MCOT)obtained by the second transmit end device on the second bandwidth, andwherein the second MCOT comprises: a sum of transmission time periods ofall service transmissions started on the second bandwidth, or a sum oftransmission time periods of all service transmissions started on thesecond bandwidth and time intervals of all discontinuous servicetransmissions, or a sum of transmission time periods of all servicetransmissions started on the second bandwidth and a time interval of adiscontinuous service transmission satisfying a specified condition. 14.The transmit end device according to claim 9, wherein the processor isfurther configured to: in response to determining that the result of thecomparing is that the second bandwidth is greater than the firstbandwidth, perform listening using non-random backoff based channellistening to determine whether the first bandwidth is in an idle state,and perform listening using random backoff based channel listening todetermine whether a remainder fourth bandwidth is in an idle state,wherein the fourth bandwidth is a difference between the secondbandwidth and the first bandwidth; and control the transceiver toperform the second service transmission on the second bandwidth based onboth the first bandwidth and the fourth bandwidth being found to be inan idle state.
 15. The transmit end device according to claim 9, whereinthe first service transmission comprises at least one of the followingtypes: uplink service transmission and downlink service transmission;and the plurality of times of discontinuous second service transmissioncomprise at least one of the following types: uplink servicetransmission and downlink service transmission.
 16. The transmit enddevice according to claim 9, wherein a length of a contention window ofthe random backoff based channel listening is fixed or variable.
 17. Anon-transitory computer-readable storage medium that stores a computerprogram, wherein when the computer program is executed by a computer,the computer is configured to: compare a second bandwidth carrying atleast one second service transmission and a first bandwidth, wherein thefirst bandwidth is used by a first transmit end device within a firstspecified time period on an unlicensed frequency band to complete afirst service transmission, and wherein the at least one second servicetransmission starts in a remaining time period of the first specifiedtime period after the first service transmission and ends in the firstspecified time period; perform channel listening on the second bandwidthbased on a result of the comparing; and control a transceiver to performthe second service transmission on the second bandwidth based on thesecond bandwidth being found to be in an idle state.
 18. Thenon-transitory computer-readable storage medium according to claim 17,wherein based on the result of the comparing being that the secondbandwidth is less than or equal to the first bandwidth, executing thecomputer program further causes the computer to perform listening usingnon-random backoff based channel listening to determine whether thesecond bandwidth is in an idle state.
 19. The non-transitorycomputer-readable storage medium according to claim 18, whereinexecuting the computer program further causes the computer to: comparewhether the second bandwidth carrying the second service transmission isless than or equal to a third bandwidth carrying a last discontinuoussecond service transmission preceding the second service transmission;in response to determining that a result of the comparing whether thesecond bandwidth is less than or equal to the third bandwidth is thatthe second bandwidth is less than or equal to the third bandwidth,perform listening using non-random backoff based channel listening todetermine whether the second bandwidth is in an idle state; and controlthe transceiver to perform the second service transmission on the secondbandwidth based on the second bandwidth being found to be in an idlestate.
 20. The non-transitory computer-readable storage medium accordingto claim 17, wherein the first specified time period is a first maximumchannel occupancy time (MCOT) obtained by the first transmit end deviceon the first bandwidth; and wherein the first MCOT comprises: a sum oftransmission time periods of all service transmissions started on thefirst bandwidth, or a sum of transmission time periods of all servicetransmissions started on the first bandwidth and time intervals of alldiscontinuous service transmissions, or a sum of transmission timeperiods of all service transmissions started on the first bandwidth anda time interval of a discontinuous service transmission satisfying aspecified condition.